compatibility
Drupal 6.x. site Migration from MySQL to PostgreSQL (howto)
I'm not a MySQL fun, so some troubles with MySQL database (MyISAM data corruption and too slow InnoDB) force migration of three existing Drupal 6 sites from MySQL to PostgreSQL. Since Drupal 6.2 some PgSQL-related bugs (sample) in core modules has been fixed, so I have a try.
Drupal 6.5 and PostgreSQL 8.3 compatibility
Drupal Core Modules
I've installed clean Drupal 6.5 on top of PostgreSQL 8.3.3 (with UTF8 database encoding) and played with it a lot. There is no heavy troubles, only minor ones:

